Is it posible to make listbar items in a group visible or not visible at run time?
The UltraWinListBar is an older control that has been replaced by the UltraWinExplorerBar. To get the same look and feel set the explorerbar.style property to ListBar.
This UltraWinExplorerBar also has additional features. One of which seems to be the visibility of items. Once you migrate to the new control, you should see a visible property off of each item.